A7330

A7330 AITSEMI | Alldatasheet

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AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 1 - DESCRIPTION FEATURES A7330 is a wide input voltage, high efficiency step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. A7330 provides up to 3.1A output current at 125kHz switching frequency. A7330 integrates control scheme to achieve high-accuracy constant current control without the expensive, high accuracy current sense resistor. It also integrates adaptive gate drive to achieve excellent EMI performance passing EN55022 Class B EMC st andard without adding additional EMI components while maintaining high conversion efficiency. Protection features include cycle -by-cycle current limit, thermal shutdown, and frequency foldback at short circuit. The A7330 is available in PSOP8 package.

ORDERING INFORMATION

SPQ: 4,000pcs/Reel MP8 A7330MP8R A7330MP8VR Note V: Halogen free Package R: Tape & Reel AiT provides all RoHS products  Up to 3.1A output current  125kHz Switching Frequency Eases EMI Design  91% Efficiency (VOUT=5V@2.4A at VIN=12V)  Resistor Programmable for Output Cable Drop Compensation  Cycle-by-Cycle Current Limit, Input Over Voltage Protect, Thermal Shutdown, Input Under Voltage Lockout  Integrated Soft Start  ±7.5% CC Accuracy  ±2% CV Accuracy  High-Side RDSON 50mΩ  Available in PSOP8 package APPLICATION  Car Charger/ Adaptor  General-Purpose CV/CC Power Supply  Rechargeable Portable Devices TYPICAL APPLICATION

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 2 - PIN DESCRIPTION Top View Pin # Symbol Function

1 HSB

High Side Bias Pin. This provides power to the internal high-side MOSFET gate driver. Connect a 22nF capacitor from HSB pin to SW pin. 2 IN Power Supply Input. Bypass this pin with a 10μF ceramic capacitor to GND, placed as close to the IC as possible. 3 SW Power Switching Output to External Inductor.

4 GND

Ground. Connect this pin to a large PCB copper area for best heat dissipation. Return FB, COMP, and ISET to this GND, and connect this GND to power GND at a single point for best noise immunity. 5 FB Feedback Input. The voltage at this pin is regulated to 800mV. Connect to the resistor divider between output and GND to set the output voltage. 6 COMP Error Amplifier Output. This pin is used to compensate the converter. 7 NC No connection.

8 ISET

Output Current Setting Pin. Connect a resistor from I SET to GND to program the output current. Exposed Pad Heat Dissipation Pad. Connect this exposed pad to large ground copper area with copper and vias.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 3 - ABSOLUTE MAXIMUM RATINGS VIN, IN to GND -0.3V ~ 32V VSW, SW to GND -1V ~ VIN+1V VGATE, HSB to GND VSW-0.3V ~ VSW+7V VIO, FB, ISET, COMP to GND -0.3V ~ 6V TSTG, Storage Temperature Range -40℃ ~ 150℃ TJ, Operating Junction Temperature -40℃ ~ 150℃ ESD Human Model 4kV Stress beyond above listed “Absolute Maximum Ratings” may lead permanent damage to the device. These are stress ratings only and operations of the device at these or any other conditions beyond those indicated in the operational sections of the specifications are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 4 -

ELECTRICAL CHARACTERISTICS

TA =+25°C, unless otherwise noted. Parameter Conditions Min. Typ. Max. Unit Input Voltage 6.4 - 30 V Input Voltage Surge - - 32 V VIN UVLO Turn-On Voltage Input Voltage Rising 5.6 6 6.4 V VIN UVLO Hysteresis Input Voltage Falling - 0.5 - V Standby Supply Current VFB=1V - 0.88 1.4 mA Feedback Voltage 785 800 815 mV Internal Soft-Start Time - 500 - μs Error Amplifier Transconductance VFB=VCOMP=0.8V ΔICOMP=±10μA - 650 - μA/V Error Amplifier DC Gain - 4000 - V/V Switching Frequency VFB=0.8V - 125 - kHz Foldback Switching Frequency VFB=0V - 18 - kHz Maximum Duty Cycle - 87 - % Minimum On-Time - 300 - ns COMP to Current Limit Transconductance VCOMP=1.7V 3.47 - A/V Secondary Cycle-by-Cycle Current Limit 6.4 - A Slope Compensation Duty=DMAX - 3 - A ISET Voltage - 1 - V ISET to IOUT DC Room Temp Current Gain IOUT/ISET，RISET=25kΩ - 90000 - A/A CC Controller DC Accuracy RISET=24.9kΩ, VOUT=4.0V - 3500 - mA Thermal Shutdown Temperature Temperature Rising - 155 - ℃ Thermal Shutdown Temperature Hysteresis Temperature Falling - 25 - ℃

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 5 - BLOCK DIAGRAM

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 6 - DETAILED INFORMATION

Application Information

As seen in Function Block Diagram, the A7330 is a peak current mode pulse width modulation (PWM) converter with CC and CV control. The converter operates as follows: A switching cycle starts wh en the falling edge of the Oscillator clock output causes the High -Side Power Switch to turn on and the Low-Side Power Switch to turn off. With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy in the magnetic f ield. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes high, the High-Side Power Switch turns off. At this point, the SW side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using HSB as the positive rail. This pin is charged to V SW+5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 0.8V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Output current will increase until it reaches the CC limit set by the ISET resistor. At this point, the device will transition fr om regulating output voltage to regulating output current, and the output voltage will drop with increasing load. The Oscillator normally switches at 125kHz. However, if FB voltage is less than 0.6V, then the switching frequency decreases until it reaches a typical value of 18kHz at VFB = 0.15V. Thermal Shutdown The A7330 disables switching when its junction temperature exceeds 155 ℃ and resumes when the temperature has dropped by 25℃. Output Voltage Setting The figure shows the connections for setting the output voltage.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 7 - Select the proper ratio of the two feedback resistors R FB1 and RFB2 based on the output voltage. Adding a capacitor in parallel with R FB1 helps the system stability. Typically, use R FB2≈10kΩ and determine R FB1 from the following equation: RFB1=RFB2  10.8V VOUT CC Current Setting A7330 constant current value is set by a resistor connected between the I SET pin and GND. The CC output current is linearly proportional to the current flowing out of the I SET pin. The voltage at I SET is roughly 1V and the current gain from I SET to output is roughly 90000. To determine the proper resistor for a desired current, please refer to figure below. Output Current vs. RISET CC Current Line Compensation When operating at constant current mode, the current limit increase slightly with input voltage. For wide input voltage applications, a resistor R C may be added to comp ensate line change and keep output high CC accuracy, as shown figure below.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 8 - Inductor Selection The inductor maintains a continuous current to the output load. This inductor current has a ripple that is dependent on the inductance value. Higher inducta nce reduces the peak -to-peak ripple current. The trade off for high inductance value is the increase in inductor core size and series resistance, and the reduction in current handling capability. In general, select an inductance value L based on ripple current requirement: L = RIPPLELOADMAXSW IN OUTIN OUT K x I x ∫xV )V(Vx V  Where V IN is the input voltage, V OUT is the output voltage, f SW is the switching frequency, I LOADMAX is the maximum load current, and K RIPPLE is the ripple factor. Typically, choose K RIPPLE=30% to correspond to the peak-to-peak ripple current being 30% of the maximum load current. With a selected inductor value the peak-to-peak inductor current is estimated as: ILPK-PK = SWIN OUTIN OUT ∫ x V )V(Vx V x L The peak inductor current is estimated as: ILPK = ILOADMAX +

1 ILPK-PK

The selected inductor should not saturate at ILPK. The maximum output current is calculated as: IOUTMAX = ILIM - ILIM is the internal current limit, which is typically 5.4A, as shown in Electrical Characteristics Table.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 9 - External High Voltage Bias Diode It is recommended that an external High Voltage Bias diode be added when the system has a 5V fixed input or the power supply generates a 5V output. This helps improve the efficiency of the regulator. The High Voltage Bias diode can be a low cost one such as IN4148 or BAT54, as figure shown below. This diode is also recommended for high duty cycle operation and high output voltage applications. Input Capacitor The input capacitor needs to be carefull y selected to maintain sufficiently low ripple at the supply input of the converter. A low ESR capacitor is highly recommended. Since large current flows in and out of this capacitor during switching, its ESR also affects efficiency. The input capacitance needs to be higher than 10μF. The best choice is the ceramic type, however, low ESR tantalum or electrolytic types may also be used provided that the RMS ripple current rating is higher than 50% of the output current. The input capacitor should be placed c lose to the IN and G pins of the IC, with the shortest traces possible. In the case of tantalum or electrolytic types, they can be further away if a small parallel 0.1μF ceramic capacitor is placed right next to the IC. Output Capacitor The output capacitor also needs to have low ESR to keep low output voltage ripple. The output ripple voltage is: VRIPPLE = IOUTMAX x KRIPPLE x RESR + OUT 2SW IN LC∫ x 28 V Where I OUTMAX is the maximum output current, K RIPPLE is the ripple factor, R ESR is the ESR of the out put capacitor, fSW is the switching frequency, L is the inductor value, and C OUT is the output capacitance. In the case of ceramic output capacitors, RESR is very small and does not contribute to the ripple. Therefore, a lower capacitance value can be used for ceramic type. In the case of tantalum or electrolytic capacitors, the ripple is dominated by R ESR multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR. For ceramic output capacitor, typically cho ose a capacitance of about 22μF. For tantalum or electrolytic capacitors, choose a capacitor with less than 50mΩ ESR.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 10 - Rectifier Diode Use a Schottky diode as the rectifier to conduct current when the High-Side Power Switch is off. The Schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage. Stability Compensation The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in figure below. NOTE ①: CCOMP2 is needed only for high ESR output capacitor The DC loop gain of the system is determined by the following equation: AVDC = OUTI 0.8V x AVEA x GCOMP The dominant pole P1 is due to CCOMP: ∫P1 = COMPVEA EA CA2 G The second pole P2 is the output pole: ∫P2 = OUTOUT OUT CV2 I The first zero Z1 is due to RCOMP and CCOMP: ∫Z1 = COMPCOMPCR2 And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used): ∫P3 = COMP2COMPCR2 The following steps should be used to compensate the IC:

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 11 - STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP: RCOMP = 0.8Vx G10G ∫CV2 COMPEA SWOUTOUT =5.17 x 107VOUTCOUT………… (Ω) STEP 2. Set the zero fZ1 at 1/4 of the cross over frequency. If RCOMP is less than 15kΩ, the equation for CCOMP is: CCOPM = COMP R If RCOMP is limited to 15kΩ, then the actual cross over frequency is 6.58 / (VOUTCOUT). Therefore: CCOMP = 6.45 x 10-6VOUTCOUT………(F) STEP 3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the cross over frequency, an additional compensation capacitor CCOMP2 is required. The condition for using CCOMP2 is: RESRCOUT≥   OUT OUT x V,0.06C 1.77x10Min ………… (Ω) And the proper value for CCOMP2 is: CCOMP2 = COMP ESRCOUTOUT R RC Though CCOMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value CCOMP2 such as 100pF may improve stability against PCB layout parasitic effects. CC Loop Stability The constant -current control lo op is internally compensated over the 2000mA -3500mA output range. No additional external compensation is required to stabilize the CC current. Output Cable Resistance Compensation To compensate for resistive voltage drop across the charger's output cable, the A7330 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. Use the curve in figure below to choose the proper feedback resistance values for cable compensation. R FB1 is the high side resistor of voltage divider.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 12 - Delta Output Voltage vs. Output Current In the case of high RFB1 used, the frequency compensation needs to be adjusted correspondingly. As show in figure below, adding a capacitor in paralleled with RFB1 or increasing the compensation capacitance at COMP pin helps the system stability. PC Board Layout Guidance When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. 1） Arrange the power components to reduce the AC loop size co nsisting of C IN, IN pin, SW pin and the schottky diode. 2） Place input decoupling ceramic capacitor CIN as close to IN pin as possible. CIN is connected power GND with vias or short and wide path. 3） Return FB, COMP and I SET to signal GND pin, and connect the signal GND to power GND at a single point for best noise immunity. Connect exposed pad to power ground copper area with copper and vias. 4） Use copper plane for power GND for best heat dissipation and noise immunity. 5） Place feedback resistor close to FB pin. 6） Use short trace connecting HSB-CHSB-SW loop.

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 13 -

PACKAGE INFORMATION

Dimension in PSOP8 Package (Unit: mm) Symbol Millimeters Inches Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.050 0.150 0.002 0.006 A2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.007 0.010 D 4.700 5.100 0.185 0.200 D1 3.202 3.402 0.126 0.134 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 E2 2.313 2.513 0.091 0.099 e 1.270 BSC 0.050 BSC L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8°

AiT Semiconductor Inc. www.ait-ic.com A7330 DC-DC CONVERTER BUCK (STEP-DOWN) SENSORLESS CC/CV REV2.0 - JAN 2016 RELEASED, MAR 2020 UPDATED - - 14 - IMPORTANT NOTICE AiT Semiconductor Inc. (AiT) reserves the right to make changes to any its product, specifications, to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of relevant informatio n to verify, before placing orders, that the information being relied on is current. AiT Semiconductor Inc. 's integrated circuit products are not designed, intended, authorized, or warranted to be suitable for use in life support applications, devices or systems or other critical applications. Use of AiT products in such applications is understood to be fully at the risk of the customer. As used herein may involve potential risks of death, personal injury, or servere property, or environmental damage. In o rder to minimize risks associated with the customer's applications, the customer should provide adequate design and operating safeguards. AiT Semiconductor Inc . assumes to no liability to customer product design or application support. AiT warrants the performance of its products of the specifications applicable at the time of sale.